The Core A Vector Development Facility is designed to serve several Projects of this Program Project Grant of the Institute for Genetic Medicine. The Core Facility will provide five projects with routine and specialized services for design, production, utilization and analysis of gene therapy retroviral vectors. This Core was established to provide a cost-effective and centralized service for vector development and packaging cells required for Projects 1-5. These Projects require retroviral vectors or packaging cell supernatants. This Core will provide reliable and quality- controlled routine measurements and monitoring of viral titer, certify the structure of the constructs, and the absence of helper or replication- competent virus.